A social-networking system, such as a social-networking website, enables its users to interact with it and with each other through the system. The social-networking system may create and store a record, often referred to as a user profile, in connection with the user. The user profile may include a user's demographic information, communication channel information, and personal interests. The social-networking system may also create and store a record of a user's relationship with other users in the social-networking system (e.g., social graph), as well as provide services (e.g., wall-posts, photo-sharing, event organization, messaging, games, or advertisements) to facilitate social interaction between users in the social-networking system. The social-networking system may transmit contents and messages related to its services to a user's client device over a network.